Field
The present disclosure relates generally to electrosurgery and electrosurgical systems and apparatuses, and more particularly, to an electrosurgical apparatus to generate a dual plasma stream and method thereof.
Description of the Related Art
High frequency electrical energy has been widely used in surgery. Tissue is cut and bodily fluids are coagulated using electrosurgical energy.
Electrosurgical instruments generally comprise “monopolar” devices or “bipolar” devices. Monopolar devices comprise an active electrode on the electrosurgical instrument with a return electrode attached to the patient. In monopolar electrosurgery, the electrosurgical energy flows through the active electrode on the instrument through the patient's body to the return electrode. Such monopolar devices are effective in surgical procedures where cutting and coagulation of tissue are required and where stray electrical currents do not pose a substantial risk to the patient.
Bipolar devices comprise an active electrode and a return electrode on the surgical instrument. In a bipolar electrosurgical device, electrosurgical energy flows through the active electrode to the tissue of a patient through a short distance through the tissue to the return electrode. The electrosurgical effects are substantially localized to a small area of tissue that is disposed between the two electrodes on the surgical instrument. Bipolar electrosurgical devices have been found to be useful with surgical procedures where stray electrical currents may pose a hazard to the patient or where other procedural concerns require close proximity of the active and return electrodes. Surgical operations involving bipolar electrosurgery often require methods and procedures that differ substantially from the methods and procedures involving monopolar electrosurgery.
Gas plasma is an ionized gas capable of conducting electrical energy. Plasmas are used in surgical devices to conduct electrosurgical energy to a patient. The plasma conducts the energy by providing a pathway of relatively low electrical resistance. The electrosurgical energy will follow through the plasma to cut, coagulate, desiccate, or fulgurate blood or tissue of the patient. There is no physical contact required between an electrode and the tissue treated.
Electrosurgical systems that do not incorporate a source of regulated gas can ionize the ambient air between the active electrode and the patient. The plasma that is thereby created will conduct the electrosurgical energy to the patient, although the plasma arc will typically appear more spatially dispersed compared with systems that have a regulated flow of ionizable gas.
Plasma jets can broadly be grouped into “Local” and “Remote” types. FIG. 9 illustrates exemplary plasma generators including a source of electrosurgical energy 402, a gas supply 404 and a handpiece 406. As shown in FIG. 9A, in local plasma jets, the primary discharge 408 occurs entirely within the hand piece 406, and the flowing inert gas 410 draws out only the most long-lived radical molecules and activated or ionized atoms. Consequently, it provides the weakest effect on the target surface 412, but since no current flows to or from that surface, an insulating surface is suitable. FIG. 9A illustrates a capacitively coupled and inductively coupled plasma jet.
In remote plasma jets, as shown in FIG. 9B, the plasma discharge 408 extends from the hand piece 406 all the way to the target surface 414, and so is said to be “remote” to the hand piece 406. Since the discharge 408 touches the target surface 414, short-lived, highly energetic radicals and ions are present at the surface, providing a very strong effect. The drawback is that the surface 414 must be conductive, and have sufficient electrical capacitance to accommodate the displacement currents that support the remote plasma discharge. For example, using J-Plasma on a mouse will require a return pad to increase the overall equivalent capacitance, while on a person of significant size, no return pad is needed.
Therefore, a need exists for techniques to generate plasma for surgical applications where the plasma will have a strong effect at the surgical site while not requiring a conductive surface or return pad.